Sole structure for footwear



June fr J. H. FLlNK 2,379,139

SOLE STRUCTURE FOR FOOTWEAR v Filed June 26, 1943 MEL 1 m John fiz 27k jig/1 Patented June 26, 1945 SOLE STRUCTURE FOR FOOTWEAR.

John H. Flink, Watertown, Mass, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application June 26, 1943, Serial No. 4%,442

6 Claims. (01. 36-195) This invention relates to sole structures for various articles of footwear and is particularly useful in connection with middle soles for socalled platform type sandals and slippers. The invention aims to provide improved comfort, longer life, and generally improved efliciency and satisfaction in such soles by providing improved bendin and flexing characteristics, especially in .the ball and toe portions of the sole, and by providing means for distributing the bending and flexing uniformly over a substantial area of the sole.

Prior workers have sought to attain similar results but only with indifferent success. Thus, it has been proposed to score or to perforate the inner faces of shoe sole parts in order to improve their flexibility. Experience has shown, however, that mere scoring is ineffective to provide any substantially increased flexibility in materials ordinarily used in sole structures. Perforating the sole member along parallel lines or actually outing parallel slots or grooves in the sole are somewhat more effective in increasing flexibility, but

these expedients introduce even more serious drawbacks. They require actual removal of a considerable quantity of sole material. Such removal of material weakens the structure and has been found to result in much quicker breakdown of the sole part with resulting impairment of the life and Wearing characteristics of the shoe. Further, soles which have been scored or perforated exhibit a marked tendency to localized bending. That is, the sole is likely to bend principally along One scored line or along one perforated line. Such localized bending, of course, greatly accelerates failure at that point and generally reduces the comfort of one wearing the shoe.

According to the present invention, bending characteristics of shoe sole members are greatly improved and the bending is effectively distributed over a relatively wide area, all without undesirable weakening of the sole structure. This is accomplished, in a preferred embodiment, by pressurally deforming the inner face of the sole member to provide therein a series of linear indentations definin intervening ridges extending transversely of the sole. No material is removed but the material which initially occupied the indentations is displaced and compacted into adjacent portions of the sole thus serving to strengthen such portions against breakdown. The configuration and disposition of the indentations and ridges are such as to facilitate ready flexing without crowding. Special materials are utilized in the sole structure to facilitate the pressure deformation and to insure maintenance of the with a sole member in place ready to be operated upon by the apparatus, and

Fig. 4 is a perspective view showing an article of footwear embodying the invention in a preferred form, portions of the structure being broken away and sectioned for clarity of illustration.

The numeral I0 designates generally a sole structure which, for purposes of illustration, has been shown as a middle sole for a platform type sandal. The sole structure I0 includes a body l'l having a heel portion I2, a shank portion I3-and a ball and toe portion I 4. In a typical sandal, the middle sole will have a substantial thickness of, for example, about in the ball and toe portion hi, the other portions varying in thickness as in the usual sole structure. A strip of rubberized fabric I5 is placed around the edgesof the body II and folded inward for a substantial distance over both the inner and outer faces-of the body for subsequent bonding to the insole and outsole elements, respectively, so that the entire shoe structure may be well secured together;

The body I I may be formed of any of a variety of materials which may be'deformed under localized pressure and which have the property of substantially retaining such local pressure deformations. Different portions of the body may be formed of different materials so long as the inner face of the ball and toe portion l4 and a substantial thickness of the underlying body is formed of material having the characteristics indicated. Generally, an artificially formed fibrous material such as coarse felt, hair felt, pricked felt, sisal, or the like should be used. Natural leather is not contemplated for use in the invention. The term artificial fibrous material having substantially the deformation characterisctics of coarse felt accordingly will be employed to designate the materials contemplated by the invention in contradistinction to materials such as leather which are to be excluded. Also, the artificial fibrous material desirably should include an impregnant or binder such as rubber or resinous material which will assist in retaining the pressurally-deformed configuration of the sole face. In some instances it may be desirable to provide a backing layer of rubberized fabric I6 or the like to provide reinforcement.

The requisite pressure deformation of the sole may be effected by means of any convenient apparatus such as the conventional fluid-pressureoperated die-press IB shown in Fig. 3. The press is provided with a smooth die-plate l9 adapted to support the Work and a configured die-plate 20 adapted to engage the work, the configured die 20 being mounted on the end of a vertically reciprocable member 2| actuated as by means of an air cylinder 22.

The working face of the die 20 is provided with a series of parallel ridges or teeth 23 extending transversely of the die in closely spaced parallel relation. The individual teeth have relatively sharp peaks but are broadened considerably at the bases. Also the teeth are spaced apart at the bases by distances substantially equal to the width of the teeth at the. bases. The die preferably has the outline of a flattened oval, the two ends being bowed outwardly as shown at 24 to conform generally to the shape of the sole in the ball portion. The width of the die, i. e., the length of the teeth 23, should be somewhat less than the width of the sole structure to be operated upon, in order that the grooves pressed into the sole structure may terminate short of the margins of the-sole. The die face as a whole may be either fiat or curved to conform generally to the configuration of the sole member to be pressed, but usually it will be flat as shown in the drawing.

The prepared sole structure ID is placed in the die-press l8 with the inner face of the ball and toe portion l4 exposed to the configured die member 20. The ball and toe portion has a generally planar configuration on both faces at this stage. Pressure is applied to the cylinder 22 and the die 20. is. forced into the deformable body of the sole. Best results are obtained if the thickness of the sole body is sufficiently great that the die teeth penetrate about two-thirds to three-fourths through the body when fully depressed. Preferably at least half the thickness of the body should be penetrated but in no event should the die teeth be, permitted to penetrate completely through the body ll.

Such pressure deformation produces in the body It a series of closely spaced parallel grooves or indentations 2-5, 25 which are relatively wide at the inner face of the sole body but taper gradually to a narrower width, in some instances a mere line, at the depths of the indentations. Intervening ridges 26, 26 are formed between the grooves. The peaks of the ridges usually will be gently rounded, as shown, by reason of displacement of the fibrous structure during the indenting operation. Likewise, all the material which initially occupied the indented zones is displaced into the adjacent regions so that effective flexibility-providing grooves are produced without removing any material whatever. The grooves 25, 25 preferably do not extend to the edges of the sole structune but terminate a substantial distance inward at each side in order to avoid edge crinkling in the finished shoe.

A middle sole structure prepared as described may be embodied in various articles of footwear such as the platform type slipper or sandal illustrated in Fig. 4. Such an article may comprise an upper member 3| which may be either a continuous upper or an open work upper such as a strap-like structure, formed of fabric, rubberized fabric, leather, artificial leather, or other suitable material. The upper 3| is adhesively secured or otherwise attached to the middle sole ID with the indented face of the middle sole directed upward or toward the inside of the article. An insole 32 made of any appropriate material overlies the top of the middle sole and covers its indented portion, the inner sole usually being cemented in place. An outsole 33 made of leather, artificial leather, rubber composition or other appropriate material is attached in the usual manner to the lower or outer face of the middle sole Ill.

Such an article of footwear fiexes with ease and the flexing is distributed over a, wide area; the tendency of the midsole to break down under repeated fiexure is minimized; and wrinkling of the edge covering fabric I5 and breakdown at the edges such as that which has accompanied prior structures of this type are substantially eliminated; all to the end that improved comfort, better appearance, and longer service life are provided.

The invention has been described as applied to a middle sole for a platform type sandal but it will be appreciated that the principles herein set out may be applied to other sole members designed for use in a variety of different types of footwear. Also'numerous variations and modifications may be made in the specific materials, apparatus, and procedures hereinabove described without departing from the sp ri and 8 1 Of e invention as defined by the appended claims.

This application is a continuation' in-part of my copending application Serial No. 426,737, filed January 14, 1942.

I claim:

l. A sole structure for an article of footwear comprising a body having a ball and toe portion of substantial thickness, said body being formed of artificial fibrous material having substantially the deformation characteristics of coarse felt and having a plurality of linear indentations defining intervening ridges extending transversely of the body in closely spaced relation in the inner face of said ball and toe portion but terminating a substantial distance inward from the margins of the body, the indentations having substantial depth and being Wider at the inner face of the body than in the depths of the indentations, the

fibrous structure in the indented region being more compact than in the unindented region as a result of displacement of fibers accompanying pressure indentation of the material, whereby bending of the sole structure is facilitated and distributed over a substantial area.

2, A middle sole structure of the platform type for an article of footwear such as a sandal or slipper, saidstructure having a heel portion, a shank portion, and a ball and toe portion, at least the ball and toe portion being formed of artificial fibrous material having substantially the deformation characteristics of coarse felt and being readily deformable under localized pressure and capable of substantially retaining localized pressure deformations, saidstructure having a plurality of transversely extending linear indentations defining intervening ridges pressed in closely spaced relation in the inner face of said ball and toe portion, the indentations terminating sub stantial' distances inward from the margins of the sole structure and havingsubstanti'al depth,

whereby bending of the ball portion is facili-.

tated and distributed over a substantial area.

3. A middle sole structure of the platform type for an article of footwear such as a sandal or slipper, said structure having a heel portion, a shank portion and a ball and toe portion, at least the ball and toe portion being formed of artificial fibrous material having substantially the deformation characteristics of coarse felt and including a binder for the fibrous material, said structure having a plurality of transversely extending linear indentations defining intervening ridges pressed in closely spaced parallel relation in the inner face of said ball and toe portion, the indentations having substantial depth and being wider at the inner face of the body than in the depths of the grooves, the indentations and ridges terminating substantial distances inward from the margins of the sole structure, the fibrous structure in the indented region being more compact than in the unindented region and the ridges having gently rounded contours as a result of displacement of fibers accompanying pressure indentations of the material, whereby bending of the middle sole is facilitated in the ball region and such bending is distributed over a substantial area.

4. An article of footwear of the platform type comprising a middle sole having a ball and toe portion formed of artificial fibrous material having substantially the deformation characteristics of coarse felt, the inner face of said ball and toe portion having pressed therein a series of transverse indentations and intervening ridges extending in closely-spaced parallel relation across the major portion of the Width of the sole but terminatingshort of its margins; an outsole secured to the outer face of the middle sole; an inner sole overlying the inner face of the middle sole' and covering the indented zone; and an upper member secured to at least one of the said sole members.

5. An article of footwear of the platform type comprising a middle sole having a ball and toe portion formed of artificial fibrous material having substantially the deformation characteristics of coarse felt and including a binder, the inner face of said ball and toe portion having pressed therein a series of transverse indentations and intervening ridges extending in closely-spaced parallel relation across the major portion of the Width of the sole .but terminating short of its margins; the fibrous structure in the indented region being more compact than in the unin-' dented region as a result of displacement of fibers accompanying pressure indentation of the material and the said binder assisting in retaining such deformed condition; an outsole secured to the outer face of the middle sole; an inner sole overlying the inner face of the middle sole and covering the indented zone; and an upper member secured to at, least one of the said sole members.

6. An article of footwear comprisingan outsole and an additional sole member overlying the outsole, said additional sole member having a ball and toe portion formed of compressible fibrous material and having pressed in the inner face thereof a series of transverse indentations and intervening ridges extending across the major portion of the width of the sole but terminating short of its margins.

JOHN H. FLINK. 

